WO2020021665A1

WO2020021665A1 - Vehicle brake control device and vehicle brake control method

Info

Publication number: WO2020021665A1
Application number: PCT/JP2018/027981
Authority: WO
Inventors: 遼平津越; 俊平小野寺; 卓矢岡原
Original assignee: 三菱電機株式会社
Priority date: 2018-07-25
Filing date: 2018-07-25
Publication date: 2020-01-30
Also published as: JP6833119B2; US20210146895A1; JPWO2020021665A1; DE112018007848T5

Abstract

A brake control unit (11) comprises: a required brake force calculation unit (21) that calculates a required brake force which is the brake force generated by a mechanical brake device in order to achieve the deceleration indicated by brake commands; an initial speed acquisition unit (22) that acquires an initial speed; a target pressing force calculation unit (23) that calculates a target pressing force which is the force for pressing a brake shoe against a wheel in order to achieve the required brake force; and a target pressure calculation unit (26) that calculates a target pressure indicating the pressure of fluid in a brake cylinder necessary for achieving the target pressing force, and performs feedback control to adjust the target pressure on the basis of the feedback signal acquired from a pressure sensor (15).

Description

Vehicle brake control device and vehicle brake control method

The present invention relates to a vehicle brake control device and a vehicle brake control method.

ブレーキ The brake control device mounted on the railway vehicle compresses the fluid supplied from the fluid source and supplies the compressed fluid to the brake cylinder of the mechanical brake device in order to obtain the target deceleration indicated by the brake command. An example of the main brake control device is disclosed in Patent Document 1. The railway vehicle brake control device disclosed in Patent Document 1 calculates a required braking force from a brake command, compresses a fluid supplied from a fluid source to a pressure for obtaining a required braking force, and compresses the fluid. Is supplied to the brake cylinder of the mechanical brake device. When the compressed fluid is supplied to the brake cylinder, the brake shoe is pressed against the wheel, and a braking force is obtained.

JP-A-2003-291797

ブレーキ Brake force is obtained by pressing the brake shoe against the wheel as described above. The braking force is expressed as a product of a friction coefficient of a contact surface between the brake shoe and the wheel and a pressing force that is a force for pressing the brake shoe against the wheel. Even if the brake command is the same, if the friction coefficient changes depending on, for example, the speed of the vehicle at the start of braking, the magnitude of the pressing force, and the like, the braking force may differ. As a result, the stop position of the vehicle may vary and may deviate from the target position.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a vehicular brake control device and a vehicular brake control method that suppress a variation in braking force with respect to the same brake command.

In order to achieve the above object, a vehicle brake control device according to the present invention includes a brake cylinder and a friction material that operates in accordance with the pressure of a fluid inside the brake cylinder. This is a vehicle brake control device that controls a mechanical brake device that generates a braking force by pressing a friction material. The vehicle brake control device includes a required brake force calculation unit, an initial speed acquisition unit, a target pressing force calculation unit, a target pressure calculation unit, and an output unit. The required braking force calculation unit acquires a brake command indicating a target deceleration of the vehicle, and calculates a required braking force that is a braking force required to obtain the target deceleration. The initial speed acquisition unit acquires the speed of the vehicle in response to the acquisition of the brake command by the necessary braking force calculation unit. The target pressing force calculation unit, as a friction coefficient of the contact surface between the friction material and the rotating body, an initial speed which is the speed of the vehicle acquired by the initial speed acquisition unit, and a pressing force which is a force pressing the friction material against the rotating body. Is used to calculate a target pressing force which is a force for pressing the friction material against the rotating body in order to obtain the necessary braking force from the average friction coefficient and the required braking force. The target pressure calculating section calculates a target pressure indicating a pressure of a fluid inside the brake cylinder necessary for obtaining a target pressing force. The output unit compresses the fluid supplied from the fluid source according to the target pressure, and supplies the compressed fluid to the mechanical brake device.

According to the present invention, the friction material is rotated in order to obtain the required braking force from the average friction coefficient that changes depending on the initial speed and the pressing force that is the force pressing the friction material against the rotating body, and the required braking force. The target pressing force, which is the force pressing against the body, is calculated. Then, by supplying fluid compressed to the mechanical brake device in accordance with the target pressure indicating the pressure of the fluid inside the brake cylinder required to obtain the target pressing force, the braking force varies with the same brake command. It is possible to provide a vehicular brake control device and a vehicular brake control method for suppressing such a situation.

1 is a block diagram illustrating a configuration of a vehicle brake system according to an embodiment of the present invention. 1 is a block diagram illustrating a configuration of a vehicle brake control device according to an embodiment. 5 is a flowchart illustrating an example of an operation of brake control performed by the vehicle brake control device according to the embodiment. The figure which shows the example of the average friction coefficient table which specifies uniquely the average friction coefficient from the speed and the pressing force of the vehicle in embodiment. The figure which shows the example of the calculation method of the average friction coefficient for every pressing force in the initial speed in embodiment. The figure which shows the example of the relational expression which specifies the pressing force by making average friction coefficient into a variable in embodiment. FIG. 1 is a diagram illustrating a hardware configuration of a vehicle brake control device according to an embodiment.

Hereinafter, a vehicle brake control device and a vehicle brake control method according to an embodiment of the present invention will be described in detail with reference to the drawings. In the drawings, the same or equivalent parts are denoted by the same reference numerals.

FIG. 1 shows a vehicle brake system 1 mounted on a railway vehicle as an example of a vehicle. The vehicle brake system 1 includes a brake setting device 2 that outputs a brake command according to an operation of a driver, a load detection device 3 that detects the weight of the vehicle, a speed sensor 4 that detects the speed of the vehicle, A source 5, a mechanical brake device 6 for generating a braking force of the vehicle, and a brake control device 10 for compressing a fluid supplied from the fluid source 5 in response to a brake command and supplying the compressed fluid to the mechanical brake device 6 And. In FIG. 1, the electric signal is indicated by a solid line, and the flow of the fluid is indicated by a dotted line.

The brake setting device 2 has a master controller provided in a driver's cab, and sends a brake command corresponding to an operation of the master controller by an operator to the brake control device 10. The brake command includes a brake notch indicating a target deceleration of the vehicle. The adaptive load detector 3 is attached to the vehicle, detects the weight of the vehicle including the passengers in the vehicle, the devices mounted on the vehicle, and the luggage, and sends the detected value to the brake control device 10. The speed sensor 4 includes a PG (Pulse Generator) attached to the axle, and sends a signal indicating the number of revolutions of the axle obtained from a pulse signal output from the PG to the brake control device 10. The fluid source 5 supplies air to the brake control device 10 as an example of a fluid.

The brake control device 10 compresses the fluid supplied from the fluid source 5 based on the brake command output from the brake setting device 2, the detection value of the adaptive load detector 3, and the detection value of the speed sensor 4, and performs mechanical braking. Supply to the device 6. The mechanical brake device 6 has a brake cylinder and a friction material that operates according to the pressure of the fluid inside the brake cylinder. When the pressure in the brake cylinder is increased by the air supplied from the fluid source 5 and compressed by the brake control device 10 being supplied to the brake cylinder, the friction material is pressed against a rotating body that rotates during traveling of the vehicle, Braking force is generated. The mechanical brake device 6 has a brake shoe as an example of a friction material. The brake force is generated when the brake shoe is pressed against a wheel that is an example of a rotating body. The braking force is expressed as a product of a pressing force, which is a force pressing the brake shoe against the wheel, and a friction coefficient of a contact surface between the brake shoe and the wheel.

Although the details will be described later, the brake control device 10 determines the friction coefficient of the contact surface between the friction material and the rotating body depending on the initial speed which is the speed of the vehicle acquired in response to the acquisition of the brake command and the pressing force. Then, the pressing force for obtaining the target deceleration indicated by the brake command is calculated using the average friction coefficient that changes. Then, the brake control device 10 compresses the air supplied from the fluid source 5 according to the pressure of the fluid inside the brake cylinder required to obtain the calculated pressing force, and uses the compressed air as a mechanical brake device. 6 By supplying the mechanical brake device 6 with the air compressed by the brake control device 10 based on the pressing force calculated as described above, the variation of the brake force with respect to the same brake command is suppressed.

The brake control device 10 calculates the target pressure indicating the pressure of the brake cylinder required to obtain the target deceleration indicated by the brake command, the brake control unit 11 and the air supplied from the fluid source 5 according to the target pressure. An output unit 12 that outputs compressed air to the mechanical brake device 6 and a pressure sensor 15 that detects the pressure of the air output by the output unit 12 and sends a feedback signal to the brake control unit 11 Prepare.

As shown in FIG. 2, the brake control unit 11 includes a required brake force calculation unit 21 that calculates a required brake force that is a brake force generated by the mechanical brake device 6 to obtain a deceleration indicated by the brake command, and an initial speed. , A target pressing force calculating unit 23 for calculating a target pressing force that is a force pressing the brake shoe against the wheel to obtain a required braking force, and a brake required for obtaining the target pressing force. A target pressure calculating unit that calculates a target pressure indicating the pressure of the fluid inside the cylinder and performs feedback control for adjusting the target pressure based on a feedback signal acquired from the pressure sensor. The target pressing force calculation unit 23 includes an average friction coefficient calculation unit 24 that calculates an average friction coefficient of the contact surface between the brake shoe and the wheel for each pressing force at the initial speed, and an average friction coefficient calculated by the average friction coefficient calculation unit 24. A calculation unit 25 for calculating a target pressing force from the required braking force.
The brake control unit 11 having the above configuration calculates a target pressure from a brake command acquired from the brake setting device 2, a detection value of the adaptive load detector 3, and a signal indicating the number of revolutions of the axle acquired from the speed sensor 4. , An electric command indicating the target pressure is sent to the output unit 12.

As shown in FIG. 1, the output unit 12 converts an electric command sent from the brake control unit 11 into an air command, and converts the electric command into an air command. And a relay valve 14 that compresses the compressed air and outputs the compressed air to the mechanical brake device 6. The electropneumatic conversion valve 13 adjusts the pressure of the air supplied from the fluid source 5 according to the electric command sent from the brake control unit 11 and outputs the pressure to the relay valve 14. The relay valve 14 compresses the air supplied from the fluid source 5 according to the pressure of the air output from the electropneumatic conversion valve 13, and supplies the compressed air to the mechanical brake device 6.

An outline of the operation of the brake control device 10 having the above configuration will be described with reference to FIG. The necessary braking force calculation unit 21 repeats the processing of step S11 while not acquiring a brake command (step S11; N). Upon acquiring the brake command (Step S11; Y), the necessary brake force calculation unit 21 calculates the required brake force from the target deceleration indicated by the brake command and the value detected by the adaptive load detector 3 (Step S12). The initial speed acquisition unit 22 acquires a pulse signal from the speed sensor 4 in response to the acquisition of the brake command by the required braking force calculation unit 21, and calculates an initial speed from the pulse signal (Step S13). The target pressing force calculation unit 23 uses the average friction coefficient that changes depending on the initial speed and the pressing force, and uses the average friction coefficient and the required braking force to apply the force that presses the brake shoe to the wheel to obtain the required braking force. Is calculated (step S14). The target pressure calculator 26 calculates a target pressure indicating the pressure of the fluid inside the brake cylinder necessary to obtain the pressing force calculated by the target pressing force calculator 23, and responds to the feedback signal acquired from the pressure sensor 15. To adjust the target pressure (step S15). The output unit 12 compresses the air until the pressure of the air supplied from the fluid source 5 reaches the target pressure, and supplies the compressed air to the mechanical brake device 6 (Step S16). If there is no change in the brake notch indicated by the brake command (Step S17; Y), the process returns to Step S15 and repeats the above processing. Specifically, the target pressure is calculated using the target pressing force calculated in step S14, and the target pressure is adjusted according to the feedback signal acquired from the pressure sensor 15, so that the pressure of the air supplied from the fluid source 5 is reduced. The air is compressed until the target pressure is reached, and the supply of the compressed air to the mechanical brake device 6 is repeated. The parameter used for calculating the target pressure may be different from the parameter used for calculating the previous target pressure. When the same brake command is not continuously obtained, that is, when the brake notch indicated by the brake command changes (Step S17; N), the process returns to Step S11 and repeats the above processing.

The operation of each part of the brake control device 10 that performs the above-described processing will be described in detail. When acquiring the brake command from the brake setting device 2, the necessary brake force calculation unit 21 calculates the following formula (1) based on the target deceleration α indicated by the brake command and the vehicle weight W1 detected by the adaptive load detector 3. The required braking force F1 is calculated from the following. The required braking force calculation unit 21 sends the required braking force F1 to the average friction coefficient calculation unit 24. The following formula (1) represents the required brake for each mechanical brake device 6 when the vehicle is supported by two trolleys, each trolley has four wheels, and a mechanical brake device 6 is provided for each wheel. Show power. Further, the required braking force calculation unit 21 sends the target deceleration α to the initial speed acquisition unit 22.
F1 = α · W1 / 8 (1)

The initial speed acquisition unit 22 acquires the speed of the vehicle in response to the acquisition of the brake command by the necessary braking force calculation unit 21. More specifically, the initial speed acquisition unit 22 detects a change in the target deceleration α acquired from the necessary brake force calculation unit 21, that is, a change in the brake command. When detecting a change in the brake command, the initial speed obtaining unit 22 calculates the speed of the vehicle from the pulse signal obtained from the speed sensor 4. The initial speed acquisition unit 22 sends the calculated vehicle speed to the average friction coefficient calculation unit 24. In the following description, the speed of the vehicle calculated by the initial speed acquisition unit 22 is referred to as an initial speed V _int . The change of the brake command includes a case where the brake command is input from a state where the brake command is not input, and a case where the number of notches of the brake notch included in the brake command changes, that is, a case where the target deceleration α changes. .

The average friction coefficient calculation unit 24 calculates, for each pressing force at an initial speed, the average friction coefficient of the contact surface between the friction material and the rotating body, which is predetermined for each pressing force at each of different predetermined vehicle speeds. The average coefficient of friction is calculated and sent to the calculation unit 25. More specifically, the average friction coefficient calculation unit 24 holds an average friction coefficient table that uniquely specifies the average friction coefficient from the speed and the pressing force of the vehicle. Figure average friction coefficient table shown in 4, the vehicle speed _V _1, V 2, · · ·, and _{V k,} the pressing force _N _1, N 2, · · ·, the average friction coefficient uniquely in combination with _{N m} It is for identification. For example, the average friction coefficient μ for the vehicle speed V ₁ and the pressing force N ₁ is μ ₁₁ . In the following _description, V ₁ and _{<V 2 <··· <V k} , and _{N 1 <N 2 <··· <} N m. The value of the average friction coefficient table is determined based on the results of a test run, a simulation, or the like in which the vehicle travels with a brake applied with a constant pressing force. At the same speed, the friction coefficient decreases as the pressing force increases. If the pressing force is the same, the friction coefficient decreases as the speed increases.

The average friction coefficient calculation unit 24 holding the above average friction coefficient table calculates the average friction coefficient for each pressing force at the initial speed from the value of the average friction coefficient table or the value obtained by interpolating the value of the average friction coefficient table. Is calculated.
For example, if the initial speed V _int matches any of the vehicle speeds V ₁ , V ₂ ,..., V _k defined in the average friction coefficient table, the initial speed V _int is associated with the matched vehicle speed. The average friction coefficient for each pressing force is used as the average friction coefficient for each pressing force at the initial speed V _int . For _example, if a _V int = _{V 2,} the pressing force _N _1, N 2, · · ·, average friction coefficient _{mu 21} corresponding to each of the _{N m,} μ _22, ···, a mu _2m, initial velocity V The average friction coefficient for each pressing force in _int .
Further, for example, the initial velocity _{V int} _is, if it meets the V _{1 <V} int _{<V 2,} the average friction coefficient _{mu 11} according to the speed _{V 1} of the vehicle, μ _12, ···, μ _1m and the speed of the vehicle V the average friction coefficient _{mu 21} corresponding to _2, μ _22, ···, by interpolating from mu _2m, calculates the average friction coefficient for each pressing force at an initial velocity _{V int.} The average friction coefficient calculation unit 24 performs primary interpolation as an example of interpolation, and calculates an average friction coefficient for each pressing force at the initial speed V _int . Initial velocity V _int, friction coefficient corresponding to the pushing force N ₁ in the case of performing the linear interpolation is expressed by the following equation (2). Initial velocity V _int pressing force N _{2 in,} ..., the average friction coefficient corresponding to N _m is also calculated in a similar manner, as shown by a white circle in FIG. 5, each pressing force at an initial velocity V _int The average coefficient of friction μ _int1 , μ _int2 ,..., Μ _intm is obtained.

As described above, the calculation unit 25 that has obtained the average friction coefficient calculated by the average friction coefficient calculation unit 24 uses the average friction coefficient as a variable at the initial speed from the average friction coefficient for each pressing force at the initial speed V _int. A relational expression for calculating the pressing force is derived. In detail, as shown by a straight line in FIG. 6, the calculation unit 25 calculates two adjacent points among the average friction coefficients μ _int1 , μ _int2 ,..., Μ _intm for each pressing force at the initial speed V _int. Is linearly interpolated to derive a relational expression. The relational expression shown by a straight line in FIG. 6 is represented by the following expression (3). The relational expression is a linear function that calculates the pressing force N ′ using the average friction coefficient μ ′ as a variable. In the following equation (3), A1 and B1 are coefficients, respectively, A1 is represented by the following equation (4), and B1 is represented by the following equation (5).
μ ′ = A1 · N ′ + B1 (3)
A1 = (μ _int2 −μ _int1 ) / (N ₂ −N ₁ ) (4)
B1 = (μ _int1 · N ₂ −μ _int2 · N ₁ ) / (N ₂ −N ₁ ) (5)

Then, the calculation unit 25 derives an equation relating to the pressing force from the relational expression derived as described above. The required braking force F1 can be regarded as being equal to the product of the average friction coefficient μ ′ and the pressing force N ′ as represented by the following equation (6). By substituting the following equation (6) into the above equation (1), the following equation (7) is obtained. The following equation (8), which is a quadratic equation related to the pressing force N ′, is derived from the above equation (3), which represents the relational equation indicated by a straight line in FIG. 6, and the following equation (7). The calculation unit 25 obtains a solution of the quadratic equation based on the solution formula, calculates a positive solution as the target pressing force N _tgt , and sends it to the target pressure calculation unit 26. Since the target pressing force can be obtained using the solution formula, the calculation process is simplified as compared with the case where the calculation process is repeated to obtain an optimal solution, an approximate solution, and the like. If the solution of the quadratic equation is not present, processor 25, initial velocity average friction coefficient for each pressing force at _{_{_{V int μ int1, μ int2,}}} ···, of the mu _INTM, another adjacent two points Linear interpolation is performed to derive a relational expression, and the above processing is repeated.
F1 = μ ′ · N ′ (6)
α · W1 / 8 = μ '· N' (7)
α · W1 / 8 = A1 · N ′ ² + B1 · N ′ (8)

The target pressure calculator 26 calculates a target pressure P _tgt from the pressing force N _tgt . Specifically, the target pressure calculation unit 26 divides the pressing force N _tgt by the area of a surface of the mechanical brake device 6 perpendicular to the sliding direction of the piston to obtain the target pressure P _tgt . When the piston slides due to the pressure of the fluid inside the brake cylinder, the brake is moved, and when the brake is pressed against the wheel, a braking force is generated. Target pressure calculating unit 26, in response to a feedback signal obtained from the pressure sensor 15, so that the pressure of air output of the relay valve 14 approaches the target pressure P _{tgt 'calculated} in the most recent, adjusts the target pressure P _tgt . Target pressure calculating section 26 outputs the electric command indicating the target pressure P _tgt to electropneumatic conversion valve 13.

The electropneumatic conversion valve 13 adjusts the pressure of the air supplied from the fluid source 5 according to the target pressure _Ptgt indicated by the electric command sent from the brake control unit 11 and outputs the pressure to the relay valve 14. The relay valve 14 compresses the air supplied from the fluid source 5 according to the command pressure, and supplies the compressed air to the mechanical brake device 6 using the pressure of the air output from the electropneumatic conversion valve 13 as the command pressure. . When the air compressed by the brake control device 10 is supplied to the brake cylinder as described above, the friction material is pressed against the rotating body that rotates during traveling of the vehicle, and a braking force is generated.

As described above, the brake control device 10 according to the present embodiment calculates the target pressing force from the average friction coefficient that changes depending on the initial speed and the pressing force, and the required braking force. Then, the brake control device 10 compresses the fluid to a pressure necessary to obtain the target pressing force, and supplies the compressed fluid to the mechanical brake device, so that the braking force varies with respect to the same brake command. It is possible to provide a vehicular brake control device and a vehicular brake control method that suppress the vehicle.

In a conventional brake control device that uses a friction coefficient according to an initial speed and a brake command, if the initial speed is the same and the brake command is the same, the same friction coefficient is used even when the vehicle weight is different. The pressing force is calculated. As represented by the above equation (1), when the weight of the vehicle increases, the required braking force increases. As can be seen from the above equation (6), when the friction coefficient is the same and the required braking force increases, the target pressing force increases. In the conventional brake control device, the same friction coefficient is used even when the weight of the vehicle is different. However, when the pressing force increases, the actual friction coefficient becomes smaller than the friction coefficient used for calculating the target pressing force. As a result, the actually generated braking force may be smaller than the required braking force. On the other hand, the brake control device 10 according to the present embodiment uses the average friction coefficient that varies depending on the initial speed and the pressing force, and uses a different average friction coefficient when the vehicle weight is different. Since the pressing force is calculated, it is possible to suppress excessive or insufficient braking force.

FIG. 7 is a diagram illustrating a hardware configuration example of the brake control unit 11 according to the embodiment. The brake control unit 11 includes a processor 31, a memory 32, and an interface 33 as a hardware configuration for controlling each unit. Each function of these devices is realized by the processor 31 executing a program stored in the memory 32. The interface 33 is for connecting each device and establishing communication, and may be composed of a plurality of types of interfaces as needed. FIG. 7 illustrates an example in which each of the processor 31 and the memory 32 is configured by one, but a plurality of processors 31 and a plurality of memories 32 may execute each function in cooperation with each other.

In addition, the above hardware configurations and flowcharts are examples, and can be arbitrarily changed and modified.

有し The main part that has the processor 31, the memory 32, and the interface 33 and performs the control processing can be realized by using an ordinary computer system without using a dedicated system. For example, storing and distributing a computer program for executing the above-described operation in a computer-readable recording medium (such as a flexible disk, a CD-ROM, or a DVD-ROM), and installing the computer program in the computer Thus, the brake control unit 11 that executes the above-described processing may be configured. Alternatively, the computer program may be stored in a storage device of a server device on a communication network, and the brake control unit 11 may be configured to be downloaded by a normal computer system.

When the function of the brake control unit 11 is realized by sharing an OS (operating system) with an application program or by cooperation between the OS and the application program, only the application program portion is stored in a recording medium or a storage device. May be.

It is also possible to superimpose a computer program on a carrier wave and distribute it via a communication network. For example, the computer program may be posted on a bulletin board (BBS: Bulletin Board System) on a communication network, and the computer program may be distributed via the communication network. Then, the computer program may be activated and executed in the same manner as other application programs under the control of the OS, so that the above-described processing may be executed.

実施 Embodiments of the present invention are not limited to the above-described embodiments. The mechanical brake device 6 has an arbitrary brake mechanism that mechanically applies a braking force to wheels. As an example, the mechanical brake device 6 has a brake pad, and generates a braking force by pressing the brake pad against a brake rotor that rotates with wheels. As another example, the mechanical brake device 6 has a brake shoe, and generates a braking force by pressing the brake shoe against a drum that is a cylindrical member that rotates with the axle.

The adaptive load detector 3 may be mounted on a trolley to detect a load applied to the trolley. When each truck has four wheels and a mechanical brake device 6 is provided for each wheel, and the adaptive load detector 3 detects the load W2 applied to the truck, the required braking force F2 is expressed by the following equation (9). Is calculated.
F2 = α · W2 / 4 (9)
The required braking forces F1 and F2 need not be equal to each other. For example, the required braking force of the mechanical brake device 6 attached to the front wheel in the traveling direction may be smaller than the required braking force of the mechanical brake device 6 attached to the rear wheel in the traveling direction.

The initial speed acquisition unit 22 may acquire the wheel rotation speed from an ATC (Automatic Train Control) instead of the speed sensor 4 or a TIMS (Train Information Management System). The speed of the vehicle may be obtained from.

The method of calculating the pressing force is not limited to the above example. The target pressing force calculation unit 23 holds a function for uniquely specifying the average friction coefficient from the pressing force for each vehicle speed, and uniquely calculates the average friction coefficient from the pressing force at the initial speed from the function for each vehicle speed. May be derived. The relational expression for uniquely calculating the average friction coefficient from the pressing force is not limited to a linear function, but may be a higher-order function such as a quadratic function or a cubic function. In this case, the target pressing force calculation unit 23 derives a higher-order equation relating to the pressing force, obtains an approximate solution, an optimal solution, and the like of the higher-order equation, and calculates the target solution as the target pressing force _Ntgt .

The average friction coefficient calculation unit 24 may hold an average friction coefficient table for each wheel position in the traveling direction. In this case, the average friction coefficient calculation unit 24 calculates the average friction coefficient for each pressing force at the initial speed for each wheel position. Then, for each wheel position, the calculation unit 25 derives a relational expression for calculating the pressing force using the average friction coefficient as a variable at the initial speed, and further derives an equation relating to the pressing force for each wheel position. The calculation unit 25 calculates the solution of the equation for each wheel position and calculates the target pressing force N _tgt for each wheel position.

The arithmetic unit 25 performs primary interpolation on two adjacent points among the average friction coefficients μ _int1 , μ _int2 ,..., Μ _intm for each pressing force at the initial speed V _int to derive a relational expression. , The pressing force may be estimated from the target deceleration, the initial speed, and the like, and the two adjacent points closest to the estimated pressing force may be linearly interpolated to derive a relational expression.

The present invention allows various embodiments and modifications without departing from the broad spirit and scope of the present invention. Further, the above-described embodiment is for describing the present invention, and does not limit the scope of the present invention. That is, the scope of the present invention is shown not by the embodiments but by the claims. Various modifications made within the scope of the claims and the scope of the invention equivalent thereto are considered to be within the scope of the present invention.

1 vehicle brake system, 2 brake setting device, 3 load response detector, 4 speed sensor, 5 fluid source, 6 mechanical brake device, 10 brake control device, 11 brake control unit, 12 output unit, 13 electropneumatic conversion valve, 14 relay valve, 15 pressure sensor, 21 required brake force calculation unit, 22 initial speed acquisition unit, 23 target pressing force calculation unit, 24 average friction coefficient calculation unit, 25 calculation unit, 26 target pressure calculation unit, 31 processor, 32 memory , 33 interface.

Claims

A mechanical brake device that has a brake cylinder and a friction material that operates according to the pressure of the fluid inside the brake cylinder, and that generates a braking force by pressing the friction material against a rotating body that rotates when the vehicle runs. A vehicle brake control device,
A required braking force calculation unit that obtains a brake command indicating a target deceleration of the vehicle and calculates a required braking force that is the braking force required to obtain the target deceleration,
In response to the acquisition of the brake command by the required braking force calculation unit, an initial speed acquisition unit that acquires the speed of the vehicle,
As a friction coefficient of a contact surface between the friction material and the rotating body, an initial speed that is the speed of the vehicle acquired by the initial speed acquisition unit, and a pressing force that is a force pressing the friction material against the rotating body. A target pressing force that is a force pressing the friction material against the rotating body to obtain the required braking force from the average friction coefficient and the required braking force, using an average friction coefficient that varies depending on the target friction force. Pressing force calculation unit,
A target pressure calculation unit that calculates a target pressure indicating the pressure of the fluid inside the brake cylinder necessary to obtain the target pressing force,
An output unit that compresses a fluid supplied from a fluid source according to the target pressure and supplies the compressed fluid to the mechanical brake device.
A vehicle brake control device comprising:
The target pressing force calculator,
An average friction coefficient calculating unit that calculates the average friction coefficient for each pressing force at the initial speed from the average friction coefficient that is predetermined for each pressing force at each of different predetermined speeds of the vehicle; ,
From the average friction coefficient for each pressing force at the initial speed, at the initial speed, derive a relational expression for calculating the pressing force using the average friction coefficient as a variable, and the necessary braking force is calculated as the average friction coefficient and An arithmetic unit that calculates the target pressing force by deriving an equation related to the pressing force from the relational expression and determining a solution to the equation, assuming that the product corresponds to the product of the pressing forces,
The vehicle brake control device according to claim 1, further comprising:
The average friction coefficient calculation unit holds an average friction coefficient table that uniquely specifies the average friction coefficient from the speed of the vehicle and the pressing force, and performs the pressing at the initial speed based on the value of the average friction coefficient table. Calculating the average friction coefficient for each force;
The vehicle brake control device according to claim 2.
The arithmetic unit derives the relational expression that is a linear function from the average friction coefficient for each pressing force at the initial speed, and considers that the required braking force matches the product of the average friction coefficient and the pressing force. Calculating the target pressing force by deriving a quadratic equation related to the pressing force from the relational expression and finding a solution of the quadratic equation,
The vehicle brake control device according to claim 2.
A vehicle brake control method performed by a vehicle brake control device,
A mechanical brake device that has a brake cylinder and a friction material that operates in accordance with the pressure of the fluid inside the brake cylinder, and generates a braking force by pressing the friction material against a rotating body that rotates during running of the vehicle, Calculate the required braking force that is the braking force that needs to be generated to obtain the target deceleration indicated by the brake command,
As the friction coefficient of the contact surface between the friction material and the rotating body, an initial speed which is the speed of the vehicle acquired in response to the start of the brake command, and a pressing force which is a force for pressing the friction material against the rotating body. Using the average friction coefficient that varies depending on the force, from the average friction coefficient and the required braking force, a target pressing force that is a force pressing the friction material against the rotating body to obtain the required braking force. Calculate,
In accordance with the pressure of the fluid inside the brake cylinder required to obtain the target pressing force, the fluid supplied from a fluid source is compressed, and the compressed fluid is supplied to the mechanical brake device.
Vehicle brake control method.